Combine lime juice and sugar in a large pitcher, stirring to help dissolve the sugar.Advertisement
Place berries in a fine-mesh sieve over a bowl. Use a rubber spatula to press on the berries, extracting the juice and some pulp while leaving the seeds behind. Stir the puree into the pitcher.
Just before serving, stir in seltzer. Serve over ice.
Make Ahead Tip: Prepare through Step 2, cover and refrigerate for up to 2 days.
1/2 fruit, 1 other carbohydrate